A year of complaining but nobody has thought to just implement it themselves and push a PR?
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Sending patches to ollama is less worthwhile than watching paint dry.
This has so far turned out to be the case: they ended up implementing it. And distastefully, too, exactly like the other 20 PR's would have implemented it; at the API level, that is.
My fork specifically introduces parsing of GBNF code blocks (Markdown ```gbnf) from the system prompt, so that any of the existing clients are supported out of the box without any effort on maintainer's part.